Control device

Abstract

The invention relates to a control device. The control device includes: a control unit that controls supply of power from a main battery to a sub-battery of a vehicle; and a calculation unit that calculates an estimated value of the full charge capacity of the main battery. When an error between the full charge capacity and the estimated value is greater than a predetermined value, the control unit calculates a continuous power supply time during which the neutron battery continuously supplies power to the load when the power supply is stopped, and a required time for eliminating polarization of the main battery, and stops the power supply when the continuous power supply time is equal to or greater than the required time. The calculation unit calculates the voltage after a required time has elapsed from when the power supply is stopped. The control unit resumes power supply after calculating the voltage.

Description

Technical Field

[0001] The present invention relates to a control device. Background Art

[0002] Regarding a control device for an in-vehicle battery, for example, Japanese Unexamined Patent Application Publication No. 2023-59430 discloses a point of transmitting power from a main battery to an auxiliary device battery. For example, when performing this power transmission during parking, power can be stably supplied from the auxiliary device battery to auxiliary devices such as a dash cam, so convenience can be improved.

[0003] In addition, the control device estimates the full charge capacity of the main battery and monitors its deterioration state. The full charge capacity can be estimated from the open circuit voltage (OCV) of the main battery. Summary of the Invention

[0004] However, during the execution of power transmission, the auxiliary device battery is connected to the main battery as a load, so the control device cannot accurately measure the OCV. On the other hand, when measuring the OCV after the power transmission ends, the frequency of estimating the full charge capacity becomes insufficient, and there is a possibility that its accuracy decreases. Therefore, it is difficult to estimate the full charge capacity of the main battery in a timely manner to accurately monitor the deterioration state during the execution of power transmission.

[0005] Therefore, the present invention has been completed in view of the above problems, and an object thereof is to provide a control device that can accurately monitor the deterioration state of a main battery during the execution of power transmission.

[0006] The present invention provides a control device having:

[0007] a control unit that controls power supply from a main battery of a power source of a vehicle to a sub-battery that supplies power to a load mounted on the vehicle during parking; and

[0008] a calculation unit that calculates an estimated value of the full charge capacity of the main battery based on the voltage of the main battery,

[0009] when an error between the full charge capacity and the estimated value is greater than a predetermined value, the control unit calculates a continuous power supply time during which the sub-battery continuously supplies power to the load during the stop of the power supply and a required time for eliminating polarization of the main battery, and when the continuous power supply time is equal to or longer than the required time, stops the power supply,

[0010] the calculation unit calculates the voltage after the required time has elapsed since the stop of the power supply,

[0011] the control unit resumes the power supply after calculating the voltage.

[0012] The present invention provides a control device, comprising:

[0013] a control unit that controls power supply from a main battery of a vehicle power source to a sub-battery, and the sub-battery supplies power to a load mounted on the vehicle during parking; and

[0014] a calculation unit that calculates an estimated value of the full charge capacity of the main battery based on the voltage of the main battery,

[0015] when an error between the full charge capacity and the estimated value is greater than a predetermined value, the control unit calculates a continuous power supply time for the sub-battery to continuously supply power to the load when the power supply is limited to a fixed power, and a required time for the polarization amount of the main battery to converge to a predetermined amount by restricting the power supply. When the continuous power supply time is equal to or greater than the required time, the power supply is restricted to the fixed power,

[0016] after the required time has elapsed since the power supply is restricted, the calculation unit calculates the voltage,

[0017] after calculating the voltage, the control unit releases the restriction on the power supply.

[0018] In the above control device, it may also be:

[0019] the control unit determines whether the error is greater than the predetermined value by using the elapsed time from the latest moment when the estimated value is calculated, based on the correlation between the usage time of the main battery and the full charge capacity.

[0020] In the above control device, it may also be:

[0021] after the required time has elapsed since the power supply is restricted, the calculation unit calculates the voltage based on the internal resistance value and the closed-circuit voltage of the main battery.

[0022] In the above control device, it may also be:

[0023] the load is a driving recorder mounted on the vehicle.

[0024] According to the present invention, during the execution of power transmission, the degradation state of the main battery can be monitored with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and wherein:

[0026] Figure 1This is a structural diagram showing an example of the system of the vehicle in the first embodiment.

[0027] Figure 2 This is a diagram showing an example of the correlation between the usage time and capacity of the main battery.

[0028] Figure 3 This is a flowchart showing an example of the calculation process of the estimated value of the full charge capacity.

[0029] Figure 4 This is a flowchart showing an example of the calculation process of the OCV of the main battery in the first embodiment.

[0030] Figure 5 This is a structural diagram showing an example of the system of the vehicle in the second embodiment.

[0031] Figure 6 This is a flowchart showing an example of the calculation process of the OCV of the main battery in the second embodiment. Detailed Description of the Invention

[0032] System Structure of the First Embodiment

[0033] Figure 1 This is a structural diagram showing an example of the system of the vehicle V in the first embodiment. The vehicle V includes an Electronic Control Unit (ECU) 1, a main battery 2, an auxiliary device battery 3, voltage sensors 20 and 30, current sensors 21 and 31, temperature sensors 22 and 32, a motor (MG) 50, an auxiliary device 51, and a heater 52. The vehicle V also includes a power conversion device 40, a Power Control Unit (PCU) 41, a direct current (DC)-DC converter 42, a socket 60, and relays 61 - 63.

[0034] The vehicle V is, for example, a plug-in hybrid electric vehicle (PHV) or an electrified vehicle, and travels using the motor 50 as a power source. The motor 50 is driven by the power supply from the main battery 2. The main battery 2 is, for example, a lithium-ion battery, but is not limited thereto, and may also be other storage batteries.

[0035] The current sensor 21 detects the current value of the main battery 2. The voltage sensor 20 detects the voltage value of the main battery 2. The temperature sensor 22 detects the temperature of the main battery 2. The voltage sensor 20, the current sensor 21, and the temperature sensor 22 output the detected values to the ECU 1.

[0036] The main battery 2 is charged by a charging device 90 outside the vehicle V. When charging the main battery 2, the connector 91 of the charging device 90 is connected to the socket 60. The charging device 90 can be controlled to be turned on (ON) / off (OFF) from the ECU 1. The socket 60, the power conversion device 40, the relay 61, the main battery 2, the relay 62, the PCU 41, and the motor 50 are connected in this order successively.

[0037] The power conversion device 40 converts the AC power supplied from the charging device 90 into DC power. Although not shown in the figure, the power conversion device 40 includes, for example, a filter circuit, a power factor correction (PFC) circuit, a smoothing capacitor, and a DC-DC converter. The filter circuit removes the noise contained in the AC power received by the socket 60. The PFC circuit rectifies the AC power from which the noise has been removed by the filter circuit, boosts it, and outputs it to the smoothing capacitor, making the input current close to a sine wave, thereby improving the power factor. The smoothing capacitor smooths the voltage fluctuations of the DC power from the PFC circuit. The DC-DC converter converts the voltage of the DC power smoothed by the smoothing capacitor into a voltage suitable for charging the main battery 2. In addition, the operation of the power conversion device 40 can be controlled to be turned on and off from the ECU 1.

[0038] The relay 61 is electrically connected between the power conversion device 40 and the main battery 2. The relay 61 opens and closes according to the control from the ECU 1. By closing the relay 61, the ECU 1 can supply the DC power from the power conversion device 40 to the main battery 2.

[0039] The PCU 41 performs power conversion between the main battery 2 and the motor 50 according to the control from the ECU 1. Although not shown in the figure, the PCU 41 includes: an inverter that converts a DC current into an AC current corresponding to the motor 50; and a converter that adjusts the level of the DC voltage supplied to the inverter.

[0040] The relay 62 is the system main relay. The relay 62 is electrically connected between the main battery 2 and the PCU 41. The relay 62 opens and closes according to the control from the ECU 1. When the vehicle V is running, the ECU 1 supplies the power of the main battery 2 to the PCU 41 by closing the relay 62 to drive the motor 50.

[0041] The auxiliary device battery 3 is an example of a secondary battery. The auxiliary device battery 3 is, for example, a storage battery such as a lithium-ion battery. The auxiliary device battery 3 supplies power to the auxiliary device 51 and the heater 52.

[0042] The current sensor 31 detects the current value of the auxiliary device battery 3. The voltage sensor 30 detects the voltage value of the auxiliary device battery 3. The temperature sensor 32 detects the temperature of the auxiliary device battery 3. The voltage sensor 30, the current sensor 31, and the temperature sensor 32 output the detected values to the ECU 1.

[0043] The auxiliary device 51 is an example of a load of the auxiliary device battery 3, such as a stereo, a vehicle navigation system, and a dash cam, etc. The heater 52 is connected to the auxiliary device battery 3 via the relay 63. The relay 63 opens and closes according to the control from the ECU 1. The ECU 1 closes the relay 63 to make the heater 52 generate heat to heat the main battery 2.

[0044] The DC-DC converter 42 is electrically connected between the auxiliary device battery 3, the relay 62, and the PCU 41. The DC-DC converter 42 performs voltage conversion on the power from the main battery 2 and supplies it to the auxiliary device battery 3. The ECU 1 drives the DC-DC converter 42 by outputting a pulse width modulation (PWM) signal to the DC-DC converter 42. Thereby, power is supplied from the main battery 2 to the auxiliary device battery 3 to charge the auxiliary device battery 3.

[0045] In this way, power is transmitted from the main battery 2 to the auxiliary device battery 3 according to the control of the ECU 1. In addition, the power transmission is an example of supplying power from the main battery 2 to the auxiliary device battery 3.

[0046] The ECU 1 performs power transmission when the vehicle V is parked or stopped. Thereby, the auxiliary device 51 can also operate during parking or stopping. For example, when operating the dash cam, the surrounding of the vehicle V can be monitored by the camera device, so the convenience is improved.

[0047] The ECU 1 is an example of a control device. The ECU 1 is a computer including a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM), etc. The ECU 1 makes the CPU operate according to the program stored in the ROM. The ECU 1, for example, not only performs charge control and discharge control of the main battery 2, but also monitors the deterioration of the main battery 2.

[0048] As a function of the software, the ECU 1 has a charging control unit 100 and a full charge capacity calculation unit 101. In addition, the ECU 1 has a capacity database (DB) 110, a state of charge (SOC) database 111, and a polarization elimination time database 112 stored in a storage unit such as a non-volatile memory.

[0049] The charging control unit 100 is an example of a control unit. The charging control unit 100 controls the power transmission from the main battery 2 to the auxiliary device battery 3. When the vehicle is parked or stopped, for example, the charging control unit 100 turns on the relay 62, stops the operation of the PCU 41, and drives the DC-DC converter 42 to perform power transmission.

[0050] In addition, the full charge capacity calculation unit 101 is an example of a calculation unit. The full charge capacity calculation unit 101 calculates an estimated value of the full charge capacity based on the open circuit voltage (OCV) of the main battery 2. In addition, the OCV is an example of the voltage of the main battery 2. The full charge capacity calculation unit 101 monitors the degradation state of the main battery 2 corresponding to the estimated value, for example, based on the correlation between the full charge capacity and the degradation degree of the main battery 2. The monitoring result is used, for example, to notify the replacement time of the main battery 2.

[0051] The charging control unit 100 performs power transmission during parking of the vehicle V and stops power transmission when a predetermined condition is satisfied. As a result, the auxiliary device battery 3 is disconnected from the main battery 2, and the polarization of the main battery 2 is eliminated, so that the full charge capacity calculation unit 101 can calculate the OCV with high accuracy. In addition, as a means of stopping power transmission, the charging control unit 100 can also open the relay 62, and when the connector 91 and the socket 60 are connected, it can also stop the operations of the charging device 90 and the power conversion device 40.

[0052] During the execution of power transmission, the charging control unit 100 determines whether it is necessary to calculate the estimated value of the full charge capacity by determining whether the error between the full charge capacity and the latest estimated value is greater than a predetermined value. At this time, the charging control unit 100 calculates the error of the estimated value based on the usage time of the main battery 2 by referring to the capacity DB 110. In the capacity DB 110, as described below, for example, the correlation between the usage time of the main battery 2 and the capacity is registered as mapping data.

[0053] Figure 2This is a diagram showing an example of the correlation between the usage time and capacity of the main battery 2. Based on prior experimental results or simulation results, a capacity database 110 is generated. The capacity decreases in a manner approaching 0 as the usage time elapses. The charge control unit 100 measures the usage time of the main battery 2 using a timer or the like, and when the usage time at which the error between the charge capacity and the latest estimated value reaches a predetermined value has elapsed, it is determined that the error is greater than the predetermined value.

[0054] As an example, let the latest estimated value calculated by the full charge capacity calculation unit 101 at the usage time T1 be C1 (Ah). In addition, in the monitoring of the degradation state of the main battery 2, the allowable error (hereinafter referred to as the allowable error) of the estimated value of the full charge capacity is assumed to be e (%) (0 < e < 100). The allowable error corresponds to the above-mentioned predetermined value and is determined, for example, according to the specifications of the main battery 2 and the requirements for estimation accuracy.

[0055] The charge control unit 100 calculates the value C2 (= C1 - C1 × e / 100) after reducing the allowable error e from the estimated value C1. Next, the charge control unit 100 calculates, based on the capacity database 110, the usage time T2 at which the capacity becomes C2 from the capacity database 110. In addition, the charge control unit 100 calculates the usage time T1 corresponding to C1 from the capacity database 110, and calculates the time difference ΔT (= T2 - T1). When the usage time exceeds the time difference ΔT or more from the time when the estimated value C1 was last calculated, the charge control unit 100 determines that the error between the actual full charge capacity and the estimated value is greater than the predetermined value. When the usage time does not exceed the time difference ΔT or more, the charge control unit 100 determines that the error between the full charge capacity and the latest estimated value is below the predetermined value.

[0056] In this way, the charge control unit 100 determines whether the error between the actual full charge capacity and the estimated value is greater than the predetermined value based on the correlation between the usage time of the main battery and the full charge capacity, using the elapsed time from the latest moment when the estimated value was calculated. Therefore, the charge control unit 100 can appropriately perform error determination based on the correlation between the usage time and the capacity.

[0057] In addition, the error determination is not limited to this, and it can also be performed based on the driving distance of the vehicle V when using the main battery 2. In this case, when the vehicle V travels a distance exceeding the distance corresponding to the allowable error from the driving distance at the time when the estimated value was last calculated while parked, the charge control unit 100 can determine that the error between the actual full charge capacity and the estimated value is greater than the predetermined value. Furthermore, for example, when the auxiliary device battery 3 is replaced and various monitoring parameters are reset, the charge control unit 100 can regard the error as greater than the predetermined value.

[0058] Refer again to Figure 1, when the charging control unit 100 determines that the above error is greater than a predetermined value, it calculates the continuous power supply time and the required time for depolarization elimination of the main battery 2 (hereinafter referred to as the depolarization elimination time). The continuous power supply time is the time for continuously supplying power to the auxiliary device battery 3 of the auxiliary device 51 during the stop of power transmission. When the continuous power supply time is equal to or greater than the depolarization elimination time, the charging control unit 100 stops transmitting power from the main battery 2 to the auxiliary device battery 3. Thus, after the depolarization elimination time has passed, the full charge capacity calculation unit 101 is substantially not affected by polarization and can calculate the OCV with high accuracy.

[0059] As described above, the charging control unit 100 stops power transmission when the condition of continuous power supply time ≥ depolarization elimination time is met. In contrast, when the continuous power supply time < depolarization elimination time holds, there is a possibility that the power of the auxiliary device battery 3 becomes insufficient before depolarization elimination and the auxiliary device 51 becomes inoperable when power transmission stops. Therefore, in this case, the charging control unit 100 does not stop but continues to transmit power to the auxiliary device battery 3. In this way, the charging control unit 100 can avoid inappropriate stoppage of power transmission by determining whether the above depolarization elimination time condition is satisfied.

[0060] The charging control unit 100 calculates the continuous power supply time based on, for example, the SOC of the auxiliary device battery 3 and the average power consumption of the auxiliary device 51. At this time, the charging control unit 100 calculates the SOC based on the detection values of the voltage sensor 30, the current sensor 31, and the temperature sensor 32. The charging control unit 100 calculates the power that the auxiliary device battery 3 can supply based on the SOC and calculates the continuous power supply time based on the average power consumption of the auxiliary device 51.

[0061] In addition, the charging control unit 100 calculates the depolarization elimination time based on, for example, the SOC and temperature of the main battery 2 according to the depolarization elimination time DB 112. At this time, the charging control unit 100 obtains the temperature from the detection value of the temperature sensor 22 and calculates the SOC based on the detection values of the voltage sensor 20, the current sensor 21, and the temperature sensor 22. In addition, in the depolarization elimination time DB112, mapping data indicating the correlation between the SOC and temperature of the main battery 2 and the depolarization elimination time is registered based on prior experimental and simulation results.

[0062] After the depolarization elimination time has passed since the stop of power transmission, the full charge capacity calculation unit 101 calculates the OCV of the main battery 2 and calculates an estimated value of the full charge capacity based on the OCV by the following method, for example.

[0063] FCC = 100 ÷ (SOCe - SOCs) × Is……(1)

[0064] As an example, the full charge capacity calculation unit 101 calculates the estimated value FCC according to the above formula (1). In formula (1), SOCs is the SOC of the main battery 2 when starting to accumulate the current value of the main battery 2, and SOCe is the SOC of the main battery 2 when ending the accumulation of the current value. The full charge capacity calculation unit 101 calculates the OCV based on the detection value of the voltage sensor 20 during the stop of power transmission, and calculates SOCs and SOCe from the OCV according to the SOC-DB 111. In the SOC-DB 111, the mapping data indicating the correlation between the OCV and the SOC of the main battery 2 is registered. After calculating the OCV, the charge control unit 100 resumes power transmission.

[0065] In addition, the full charge capacity calculation unit 101 obtains the current accumulation value Is by accumulating the detection values of the current sensor 21. After calculating SOCs, when the current accumulation value Is is greater than the threshold Ith, the full charge capacity calculation unit 101 calculates SOCe and calculates the estimated value FCC according to formula (1).

[0066] In this way, during the execution of power transmission, the charge control unit 100 determines whether the conditions related to the error of the estimated value of the full charge capacity and the conditions related to the polarization elimination time are satisfied, and stops power transmission when each condition is satisfied. Therefore, the ECU 1 can calculate the OCV with high precision without frequently stopping power transmission, and thus can estimate the full charge capacity. Therefore, the ECU 1 can monitor the deterioration state of the main battery 2 with high precision.

[0067] Operation of the ECU in the first embodiment

[0068] Figure 3 is a flowchart showing an example of the calculation process of the estimated value of the full charge capacity. In this example, as an example, the calculation process using the above formula (1) is given, but it is not limited thereto. This process is executed during the power transmission by the charge control unit 100 when the vehicle V is stopped or parked.

[0069] First, the full charge capacity calculation unit 101 calculates the OCV of the main battery 2 (St21). At this time, the OCV calculation process described later is executed. Next, the full charge capacity calculation unit 101 calculates SOCs from the OCV according to the SOC-DB 111 (St22).

[0070] Next, the full charge capacity calculation unit 101 starts accumulating the current value of the main battery 2 detected by the cumulative current sensor 21 (St23). Next, the full charge capacity calculation unit 101 compares the accumulated current cumulative value Is with the threshold Ith (St24). When Is ≤ Ith holds (No in St24), the process of St24 is executed again. In addition, when Is > Ith holds (Yes in St24), the accumulation of the current value is stopped (St25).

[0071] Next, the full charge capacity calculation unit 101 calculates the OCV of the main battery 2 (St26). At this time, the calculation process of the OCV described later is executed. Next, the full charge capacity calculation unit 101 calculates SOCe from the OCV based on the SOC-DB 111 (St27).

[0072] Next, the full charge capacity calculation unit 101 calculates the estimated value according to Equation (1) based on the current cumulative value Is, SOCs, and SOCe (St28). In this way, the calculation process of the estimated value of the full charge capacity is performed. In addition, the full charge capacity calculation unit 101 stores the usage time (the above T1) of the main battery 2 when the estimated value is calculated in a memory or the like.

[0073] Figure 4 It is a flowchart showing an example of the calculation process of the OCV of the main battery 2 in the first embodiment. In the above St21 and St26, this process is executed respectively.

[0074] First, the charge control unit 100 determines whether the error of the estimated value of the full charge capacity is greater than the threshold TH (St1). Regarding the determination process, the method of using the usage capacity DB 110 as described above is exemplified, but it is not limited to this. When the error of the estimated value is equal to or less than the threshold TH (No in St1), the charge control unit 100 determines that the latest estimated value has sufficient accuracy for deterioration detection, and executes the process of St1 again.

[0075] In addition, when the error of the estimated value is greater than the threshold TH (Yes in St1), the charge control unit 100 calculates the polarization elimination time through the polarization elimination time DB 112 (St2). Moreover, the charge control unit 100 calculates the continuous power supply time of the auxiliary device battery 3 during the stop of power transmission based on the SOC of the auxiliary device battery 3 and the average power consumption of the auxiliary device, etc. (St3). In addition, the calculation order of the polarization elimination time and the continuous power supply time is not limited.

[0076] Next, the charging control unit 100 compares the continuous power supply time with the polarization elimination time (St4). When the continuous power supply time < polarization elimination time holds ( "No" in St4), the charging control unit 100 determines that there is a possibility of power shortage in the auxiliary device battery 3 due to the stop of power transmission, and executes the process of St1 again.

[0077] In addition, when the continuous power supply time ≥ polarization elimination time holds ( "Yes" in St4), the charging control unit 100 determines that power can continue to be supplied from the auxiliary device battery 3 to the auxiliary device 51 even during the stop of power transmission, and stops power transmission (St5). In addition, the charging control unit 100 can also pre - charge the auxiliary device battery 3 so that the continuous power supply time ≥ polarization elimination time holds.

[0078] Next, the charging control unit 100 determines whether the polarization elimination time has elapsed since the stop of power transmission (St6). At this time, the charging control unit 100 measures the elapsed time since the stop of power transmission using a timer, for example, for determination. When the polarization elimination time has not elapsed ( "No" in St6), the process of St6 is performed again.

[0079] When the polarization elimination time has elapsed ( "Yes" in St6), the full - charge capacity calculation unit 101 determines the depolarization of the main battery 2 and calculates the OCV (St7). This OCV is used to calculate SOCs and SOCe as shown in Equation (1).

[0080] Next, the charging control unit 100 starts power transmission again (St8). In this way, the calculation process of the OCV of the main battery 2 is executed.

[0081] System structure of the second embodiment

[0082] Figure 5 is a structural diagram showing an example of the system of the vehicle V in the second embodiment. In Figure 5 it, the same reference numerals are added to the structures common to Figure 1 and their descriptions are omitted.

[0083] In addition to the same structure as in the first embodiment, the vehicle V further includes a constant - power control device 43. The constant - power control device 43 has, for example, the same circuit structure as the stabilization power supply device, is connected between the main battery 2 and the relay 62, and substantially maintains the supply power of the main battery 2 constant. The operation of the constant - power control device 43 is controlled by the ECU 1.

[0084] As a function of the software, the ECU 1 has a charging control unit 100a and a full charge capacity calculation unit 101a. In addition, the ECU 1 has a capacity DB 110, an SOC-DB 111, and a polarization convergence time database 113 stored in a storage unit such as a non-volatile memory.

[0085] The charging control unit 100a is an example of a control unit that controls the above-described power transmission. The full charge capacity calculation unit 101a is an example of a calculation unit that calculates an estimated value of the full charge capacity based on the open circuit voltage (OCV) of the main battery 2 by the same method as described above.

[0086] In order to calculate the OCV of the main battery 2, the charging control unit 100a restricts the power transmission to a fixed power (hereinafter referred to as the restricted power) by operating the constant power control device 43 instead of stopping the power transmission. As a result, the supplied power is maintained at the restricted power, and the polarization amount of the main battery 2 converges to a predetermined amount, so that the closed circuit voltage (CCV) of the main battery 2 can be calculated with high accuracy. The OCV is calculated based on the CCV as described later.

[0087] Similar to the first embodiment, the charging control unit 100a determines the error of the estimated value of the full charge capacity. When the error between the full charge capacity and the estimated value is greater than a predetermined value, the charging control unit 100a calculates the continuous power supply time and the required time (hereinafter referred to as the polarization convergence time). The continuous power supply time is the time during which the auxiliary device battery 3 of the auxiliary device 51 is continuously supplied with power when the power transmission is restricted to the restricted power. The required time is the time required for the polarization amount of the main battery 2 to converge to a predetermined amount by restricting the power transmission.

[0088] The charging control unit 100a calculates the continuous power supply time based on, for example, the SOC of the auxiliary device battery 3, the restricted power, and the average power consumption of the auxiliary device 51. At this time, the charging control unit 100 calculates the SOC based on the detection values of the voltage sensor 30, the current sensor 31, and the temperature sensor 32.

[0089] In addition, the charging control unit 100a calculates the polarization convergence time based on, for example, the SOC and temperature of the main battery 2 from the polarization convergence time DB 113. At this time, the charging control unit 100a obtains the temperature from the detection value of the temperature sensor 22 and calculates the SOC based on the detection values of the voltage sensor 20, the current sensor 21, and the temperature sensor 22. In addition, in the polarization convergence time DB 113, mapping data indicating the correlation between the SOC and temperature of the main battery 2 and the polarization convergence time when the power transmission is restricted to the restricted power is registered based on prior experimental and simulation results.

[0090] When the condition of continuous power supply time ≥ polarization convergence time is satisfied, the charging control unit 100a limits the power transmission to the limited power. In contrast, when the continuous power supply time < polarization convergence time holds, if the power transmission is restricted, there is a possibility that the power of the auxiliary device battery 3 becomes insufficient before polarization convergence and the auxiliary device 51 becomes inoperable. Therefore, in this case, the charging control unit 100a does not restrict the power transmission to the auxiliary device battery 3. In this way, by determining whether the above polarization convergence time condition is satisfied, the charging control unit 100a can avoid inappropriately restricting power transmission.

[0091] When the continuous power supply time is equal to or longer than the polarization convergence time, the charging control unit 100a limits the power transmission to the limited power. Thereby, after the polarization convergence time has elapsed, the fully charged capacity calculation unit 101a can accurately calculate the CCV in a state where the influence of polarization is suppressed.

[0092] OCV = CCV - I × r...(2)

[0093] As an example, the fully charged capacity calculation unit 101a calculates the OCV based on the CCV, current value I, and internal resistance value r of the main battery 2 using the above formula (2). The fully charged capacity calculation unit 101a obtains the current value I from the current sensor 21 and calculates the CCV based on the detection value of the voltage sensor 20.

[0094] For example, before the power transmission is restricted, the fully charged capacity calculation unit 101a plots the current value and voltage value of the main battery 2 in a two-dimensional coordinate system (I-V plot) for a predetermined time based on the detection values of the voltage sensor 20 and the current sensor 21. Next, the fully charged capacity calculation unit 101a calculates the internal resistance value r by linearly approximating the correlation between the current value and the voltage value and obtaining its slope. In addition, the calculation method of the internal resistance value r is not limited to this. For example, the fully charged capacity calculation unit 101a can calculate the internal resistance value r based on the Arrhenius law according to the correlation with the SOC and temperature of the main battery 2, or can calculate the internal resistance value r based on the usage time of the main battery 2.

[0095] In this way, after the polarization convergence time has elapsed since the power transmission was restricted, the fully charged capacity calculation unit 101a calculates the OCV based on the internal resistance value r and CCV of the main battery 2. Therefore, compared with the case of calculating the OCV using mapping data based on the CCV, for example, the fully charged capacity calculation unit 101a can calculate the OCV with higher accuracy.

[0096] The charge control unit 100a stops the operation of the constant power control device 43 after calculating the OCV, thereby releasing the restriction on power transmission. As a result, the auxiliary equipment battery 3 is charged with power corresponding to the power consumption of the auxiliary equipment 51 as a load from the main battery 2. In addition, although the limit power is not limited, when the limit power is greater than the average power consumption of the auxiliary equipment 51, the charge control unit 100a may close the relay 63 to drive the heater 52, thereby consuming the excess power.

[0097] Thus, during the execution of power transmission, the charging control unit 100a determines whether the conditions related to the error of the estimated value of the full charge capacity and the conditions related to the polarization convergence time are satisfied, and limits the power transmission to the limited power when each condition is satisfied. Therefore, the ECU 1 does not need to frequently limit the power transmission, and can estimate the full charge capacity by calculating the OCV with high accuracy. Therefore, the ECU 1 can monitor the degradation state of the main battery 2 with high accuracy.

[0098] Operation of ECU in the Second Embodiment

[0099] In this example, the calculation process of the estimated value of the full charge capacity is also performed in the same manner as in the first embodiment. In addition, the calculation process of the OCV of the main battery 2 will be described below.

[0100] Figure 6 This is a flowchart showing an example of the calculation process of the OCV of the main battery 2 in the second embodiment. This process is executed in the above-mentioned steps St21 and St26.

[0101] First, the charging control unit 100a determines whether the error of the estimated value of the full charge capacity is greater than the threshold value TH (St11) in the same manner as in the first embodiment. When the error of the estimated value is less than the threshold value TH (No in St11), the charging control unit 100a determines that the latest estimated value has sufficient accuracy for degradation detection and executes the process of St11 again.

[0102] In addition, when the error of the estimated value is larger than the threshold value TH ("Yes" in St11), the charging control unit 100a calculates the polarization convergence time based on the polarization convergence time DB 113 (St12). Furthermore, the charging control unit 100a calculates the continuous power supply time of the auxiliary equipment battery 3 during the stop of power transmission based on the SOC of the auxiliary equipment battery 3, the limited power, and the average power consumption of the auxiliary equipment (St13). In addition, the order of calculating the polarization convergence time and the continuous power supply time is not limited.

[0103] Next, the charging control unit 100a compares the continuous power supply time with the polarization convergence time (St14). When the continuous power supply time < polarization convergence time holds (the "No" of St14), the charging control unit 100a determines that there is a possibility of power shortage in the auxiliary device battery 3 due to restricted power transmission, and executes the process of St11 again.

[0104] In addition, when the continuous power supply time ≥ polarization convergence time holds (the "Yes" of St14), the charging control unit 100a determines that power can continue to be supplied from the auxiliary device battery 3 to the auxiliary device 51 even under the restriction of power transmission. Moreover, the charging control unit 100a calculates the internal resistance value r (St15), and restricts the power transmission to the restricted power by operating the constant power control device 43 (St16). In addition, the charging control unit 100a can also fully charge the auxiliary device battery 3 in advance so that the continuous power supply time ≥ polarization convergence time holds.

[0105] Next, the charging control unit 100a determines whether the polarization convergence time has elapsed since the start of restricted power transmission (St17). At this time, the charging control unit 100a, for example, uses a timer to measure the elapsed time since the power transmission stopped for the determination. When the polarization convergence time has not elapsed (the "No" of St17), the process of St17 is performed again.

[0106] When the polarization convergence time has elapsed (the "Yes" of St17), the full charge capacity calculation unit 101a determines that the polarization of the main battery 2 has been eliminated and calculates the CCV (St18). As described above, the OCV is calculated based on the CCV and the internal resistance value r (St19). This OCV is used to calculate the SOCs and SOCe according to Equation (1).

[0107] Next, the charging control unit 100a releases the restriction on power transmission (St20). In this way, the calculation process of the OCV of the main battery 2 is executed.

[0108] The above-described embodiment is a preferred example of the implementation of the present invention. However, it is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

Claims

1. A control device comprising: a control unit that controls the supply of electric power from a main battery that is a power source of the vehicle to a sub-battery that supplies electric power to a load mounted on the vehicle when the vehicle is parked; and a calculation unit that calculates an estimated value of a full charge capacity of the main battery based on a voltage of the main battery, When the error between the full charge capacity and the estimated value is greater than a predetermined value, the control unit calculates a continuous power supply time for the sub-battery to continuously supply power to the load and a required time for polarization elimination of the main battery during the stop of the power supply, and stops the power supply when the continuous power supply time is longer than the required time. The calculation unit calculates the voltage after the required time has elapsed from when the power supply is stopped, The control unit resumes the power supply after calculating the voltage.

2. A control device comprising: a control unit that controls the supply of electric power from a main battery that is a power source of the vehicle to a sub-battery that supplies electric power to a load mounted on the vehicle when the vehicle is parked; and a calculation unit that calculates an estimated value of a full charge capacity of the main battery based on a voltage of the main battery, When the error between the full charge capacity and the estimated value is greater than a predetermined value, the control unit calculates a continuous power supply time for which the sub-battery continuously supplies power to the load when the power supply is limited to a fixed power, and a required time for making the polarization amount of the main battery converge to a predetermined amount by limiting the power supply, and limits the power supply to the fixed power when the continuous power supply time is longer than the required time. The calculation unit calculates the voltage after the required time has elapsed from when the power supply is limited, The control unit releases the limitation on the power supply after calculating the voltage.

3. The control device according to claim 1 or 2, wherein: The control unit determines whether the error is larger than the predetermined value using the elapsed time from the latest time when the estimated value is calculated based on the correlation between the usage time of the main battery and the full charge capacity.

4. The control device according to claim 2, wherein: The calculation unit calculates the voltage based on the internal resistance value and the closed circuit voltage of the main battery after the required time has elapsed since the power supply was limited.

5. The control device according to claim 1 or 2, wherein: The load is a driving recorder mounted on the vehicle.

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